Process of producing intaglio-printing forms



Aug. 7, l923. HAM-,MO

v v E. SAUER PROCESS OF PRODUCING INTAGLIO PRINTING FORMS Original Filed Feb. 5. 1921 Dichromofed Gelahn.

mgm a etant Augun 7, 1923 ITE-D STATES BAUER, DI BCHLSS BITZ, NEAR. REMATE,

PECIISSi F 'PRODUGING INTAGLIO-PRINTING FORMS.

.Application tiled February 9, 1921, Serial No. 442,284. Renewed June 22, 1923.

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To all whom t may concern.'

Be itknown that'l, ERNST SAUER, a oitiaen of Germany, residing at Schloss Kaibltz, near Kemnath, Bavaria, Republic of Germany, have 'invented new and useful llmprovements in and Processes of Froducing llntaglioLlPrinting Forms (for which l have filed applications in Germany Patent No. 340003, Aug. 24, 1919; Luxemburg No. 11606,

l Jan. 21, 1920;-Switzerland No. 86,573 Jan. 19, 1920; Spain No. 72356 June-22, 1920; France No. 5094134 Feb. 5, 1920; England No. 156420 J an. 30, 1920; Norway No. 32312 Feb. 7, 1920; Denmark No. 27863 June 11, 1921;

Sweden No. 49798 Feb. 8, 1920; Belgium No. 284982 Feb. 11, 1920; Hungary No. 78196 J an. 21, 1920), of which the following is a specification.

'lhis invention relates to intaglio-printlng forms and a process of producing them in a photo-mechanical way audits object is to give such forms any reqmred depth by means of a peculiar manner of copying without manual labor and to prevent that the ink being extracted from the recesses of the inked form by the scraper ,for removing the excess of ink. With this end in view the process is carried out in the following manner illustrated in the accompanying drawing, in which:

Fig. 1 a cross-section through a transparent carrier with a layer of bichrom ated gelatine at one side,

Fig. 2 a cross-section through the same carrier with a screen-plate applied to its hichrornated layer,

Fig. 3 a screen-plate in plan, c

Fig. d is a cross section through the h1-Y chromated gelatin coated carrier after exposure through the screen, which has beenl removed and with a diapositive Yapplied to the reverseside of thearrier and after exposure through said diapositive, and

Fig. 5 is a cross section through the transparent carrier and its bichromated gelatln after exposure and development.

A plate a, Fig. 1, of a more or f'less transparentnmaterial, such as cellulold, acetylcellulose (cellon), aper or the like is at ,one side covered with a layer l5 voit a thickness of 0,06 to 0,08 mm. of bichromatedgelatine in such a manner that the gelatine firmly adheres to its carrier a. 'lhe screenplate c, Figs.- 2 and 3, (having transparent LED 'UNDER THE JPROVISIUNS 0F T ACT 0F MARCH 8, 1921, 41 STAT. lb., 1813.)

lines and opaque dots) is then applied to the bichromated-gelatine layer b and is exposed to the light until the 'lines of the screen c appear as tanned lines in the layer of gelatine b, see wedges d, Figs. 2, a and 5, which in bright sunshine requires an exposure of about 3 to 4 minutes. Now the screen c is removed and a diapositive e of the picture to lbe reproduced is applied to the reverse side of the carrier and the bichromated gelatin layer Z) is exposed to light passing through the diapositive e and the carrier b to the bichromated gelatine b, so that this portion ot itis completely tanned up to the surface of the layer, see h, i, k, Al, Figs. 4 and 5. The less transparent places of the 'diapositive allow only so much light to pass that the bichromated-gelatinel layer is only tanned to a certain depth and as below the opaque parts m and a of the dia-positive e the bichromated gelatine layer is not tanned by the exposure, on developing the plate by means of warm water the following result will be observed:

The face of the printing form is level in so -tar as the bars d, d, Flgs. 2, 4 and 5, of the screen remain of equal depth throughout the whole picture. @n the other hand the exposure from the back of the printing plate forms a reliefv which corresponds exactly with the picture, so that at the parts of the picture where less light has penetrated recesses are ytermed between the bars of they screen, which recesses are intended to hold the ink. rllhe bars of the-screen are at the surface of the bichromated-gelatne layer i5 of the same width as the lines of the screen, while they are thinner in the depth of the layer of gelatine, which is due to the fact lthat the light during the copying of the screen cannot act so intensely at lower depths ofthe layer of gelatine. These extremely fine bars in the depth of the layer ot gelatine are strengthened at the' bottom of the layer by exposure through the diapositive rom the back of the printing plate so that they do not break down during the developing process. ln consequence of the fact that the bars of the screen are thinner at the back than at the front of the printing plate, recesses are formed between the bars of the screen which at the back are Wider than at the tront.- The undercut walls of the recesses will naturally hold the i contained in the recesses more safely than bars of uniform thickness and the ink will not be drawn out of the recesses when the printing form is scraped. In order t .render the printing form vand the face of the layer of gelatine consisting of the intersecting bars of the screen better capable of resisting the ink scraper, it is preferably lightly moistened with acetic acid and then coated with a suitable varnish, such as zapon-va-rnish.

What I claim as my invention and desire to secure by United States Letters Patent is 1. The process of producing intaglio- 5 printing forms, which consists in coating a transparent carrier with a layer of bichromated-gelatine, applying an intaglio screen-plate to the face of said layer, eX- posing to the light through said screen, applying a dia-positive ofthe picture to the uncovered side of said carrier and exposing to the light through said dia-positive and developing by means of Warm water.

2. As a new article of manufacture an intaglio-printing form comprising a carrier plate having a level screen on one face and a relier` of the picture to be reproduced 'between the bars of said screen, the saidV screen and the said relief consisting of tanned bichromated-gelatine 3. As a new article of manufacture an intaglio-printing form comprising a carrier plate havinga level screen on one face, the bars of said screen being undercut and a relief of the picture to be reproduced between the said bars of said screen, the said screen and the said relief consisting of tanned bichromated-gelatine.

In testimony whereof I have signed my name toV this specification in the presence of two subscribing witnesses.

ERNST SAUER.

Witnesses GERHARD LEwNANDowsKY, GERRY SCHINNsY. 

